1 /* SPDX-License-Identifier: GPL-2.0-only */
2 #ifndef __ASM_ASM_EXTABLE_H
3 #define __ASM_ASM_EXTABLE_H
4 
5 #include <linux/bits.h>
6 #include <asm/gpr-num.h>
7 
8 #define EX_TYPE_NONE			0
9 #define EX_TYPE_BPF			1
10 #define EX_TYPE_UACCESS_ERR_ZERO	2
11 #define EX_TYPE_KACCESS_ERR_ZERO	3
12 #define EX_TYPE_UACCESS_CPY		4
13 #define EX_TYPE_LOAD_UNALIGNED_ZEROPAD	5
14 
15 /* Data fields for EX_TYPE_UACCESS_ERR_ZERO */
16 #define EX_DATA_REG_ERR_SHIFT	0
17 #define EX_DATA_REG_ERR		GENMASK(4, 0)
18 #define EX_DATA_REG_ZERO_SHIFT	5
19 #define EX_DATA_REG_ZERO	GENMASK(9, 5)
20 
21 /* Data fields for EX_TYPE_LOAD_UNALIGNED_ZEROPAD */
22 #define EX_DATA_REG_DATA_SHIFT	0
23 #define EX_DATA_REG_DATA	GENMASK(4, 0)
24 #define EX_DATA_REG_ADDR_SHIFT	5
25 #define EX_DATA_REG_ADDR	GENMASK(9, 5)
26 
27 /* Data fields for EX_TYPE_UACCESS_CPY */
28 #define EX_DATA_UACCESS_WRITE	BIT(0)
29 
30 #ifdef __ASSEMBLY__
31 
32 #define __ASM_EXTABLE_RAW(insn, fixup, type, data)	\
33 	.pushsection	__ex_table, "a";		\
34 	.align		2;				\
35 	.long		((insn) - .);			\
36 	.long		((fixup) - .);			\
37 	.short		(type);				\
38 	.short		(data);				\
39 	.popsection;
40 
41 #define EX_DATA_REG(reg, gpr)	\
42 	(.L__gpr_num_##gpr << EX_DATA_REG_##reg##_SHIFT)
43 
44 #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)		\
45 	__ASM_EXTABLE_RAW(insn, fixup, 					\
46 			  EX_TYPE_UACCESS_ERR_ZERO,			\
47 			  (						\
48 			    EX_DATA_REG(ERR, err) |			\
49 			    EX_DATA_REG(ZERO, zero)			\
50 			  ))
51 
52 #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)			\
53 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
54 
55 #define _ASM_EXTABLE_UACCESS(insn, fixup)				\
56 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
57 
58 /*
59  * Create an exception table entry for uaccess `insn`, which will branch to `fixup`
60  * when an unhandled fault is taken.
61  */
62 	.macro          _asm_extable_uaccess, insn, fixup
63 	_ASM_EXTABLE_UACCESS(\insn, \fixup)
64 	.endm
65 
66 /*
67  * Create an exception table entry for `insn` if `fixup` is provided. Otherwise
68  * do nothing.
69  */
70 	.macro		_cond_uaccess_extable, insn, fixup
71 	.ifnc			\fixup,
72 	_asm_extable_uaccess	\insn, \fixup
73 	.endif
74 	.endm
75 
76 	.macro		_asm_extable_uaccess_cpy, insn, fixup, uaccess_is_write
77 	__ASM_EXTABLE_RAW(\insn, \fixup, EX_TYPE_UACCESS_CPY, \uaccess_is_write)
78 	.endm
79 
80 #else /* __ASSEMBLY__ */
81 
82 #include <linux/stringify.h>
83 
84 #define __ASM_EXTABLE_RAW(insn, fixup, type, data)	\
85 	".pushsection	__ex_table, \"a\"\n"		\
86 	".align		2\n"				\
87 	".long		((" insn ") - .)\n"		\
88 	".long		((" fixup ") - .)\n"		\
89 	".short		(" type ")\n"			\
90 	".short		(" data ")\n"			\
91 	".popsection\n"
92 
93 #define EX_DATA_REG(reg, gpr)						\
94 	"((.L__gpr_num_" #gpr ") << " __stringify(EX_DATA_REG_##reg##_SHIFT) ")"
95 
96 #define _ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, zero)		\
97 	__DEFINE_ASM_GPR_NUMS						\
98 	__ASM_EXTABLE_RAW(#insn, #fixup, 				\
99 			  __stringify(EX_TYPE_UACCESS_ERR_ZERO),	\
100 			  "("						\
101 			    EX_DATA_REG(ERR, err) " | "			\
102 			    EX_DATA_REG(ZERO, zero)			\
103 			  ")")
104 
105 #define _ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, zero)		\
106 	__DEFINE_ASM_GPR_NUMS						\
107 	__ASM_EXTABLE_RAW(#insn, #fixup, 				\
108 			  __stringify(EX_TYPE_KACCESS_ERR_ZERO),	\
109 			  "("						\
110 			    EX_DATA_REG(ERR, err) " | "			\
111 			    EX_DATA_REG(ZERO, zero)			\
112 			  ")")
113 
114 #define _ASM_EXTABLE_UACCESS_ERR(insn, fixup, err)			\
115 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, err, wzr)
116 
117 #define _ASM_EXTABLE_UACCESS(insn, fixup)				\
118 	_ASM_EXTABLE_UACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
119 
120 #define _ASM_EXTABLE_KACCESS_ERR(insn, fixup, err)			\
121 	_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, err, wzr)
122 
123 #define _ASM_EXTABLE_KACCESS(insn, fixup)				\
124 	_ASM_EXTABLE_KACCESS_ERR_ZERO(insn, fixup, wzr, wzr)
125 
126 #define _ASM_EXTABLE_LOAD_UNALIGNED_ZEROPAD(insn, fixup, data, addr)		\
127 	__DEFINE_ASM_GPR_NUMS							\
128 	__ASM_EXTABLE_RAW(#insn, #fixup,					\
129 			  __stringify(EX_TYPE_LOAD_UNALIGNED_ZEROPAD),		\
130 			  "("							\
131 			    EX_DATA_REG(DATA, data) " | "			\
132 			    EX_DATA_REG(ADDR, addr)				\
133 			  ")")
134 
135 #endif /* __ASSEMBLY__ */
136 
137 #endif /* __ASM_ASM_EXTABLE_H */
138